½of a small onionchopped (approximately 1/4 cup) (I used a yellow onion)
2large Roma tomatoesone with the seeds completely removed and chopped, the other sliced to desired thickness
⅓cuppacked fresh basilchopped
4ounces(113g) fresh mozzarellashredded (pre-shredded is fine)
2large egg whites
Preheat oven to 350ºF (177ºC). Spray an 8" or 9" pie plate with olive oil. Set aside.
In a large skillet over medium-high heat, heat the olive oil. Add chopped onion and garlic and cook for 5-6 minutes, stirring frequently, or until tender. Remove from heat and allow to cool.
Slice one of your tomatoes in half and scoop out as many of the seeds as you can (to prevent quiche from getting soggy). After seeds are removed, chop tomato and add to onion/garlic mixture. Stir to combine.
Pack washed basil leaves into ⅓ cup measuring cup, then chop to desired size (I chopped mine quite small). Add chopped basil to onion/garlic and tomato mixture and again to combine. Spoon this mixture into the bottom of your pie plate and spread into an even layer. Top with mozzarella and set aside.
In a medium bowl, preferably with a spout, whisk the eggs, egg whites, milk, salt, and pepper until thoroughly combined. Pour the egg mixture evenly on top of cheese layer. Lay tomato slices gently on top of egg mixture (overlapping slices is fine). It is ok if egg mixture comes up over tomato slices. Sprinkle additional salt and black pepper on top of tomato layer, if desired.
Bake quiche for 50 minutes or until filling is set. Cool for 10 minutes on a wire rack before serving. Cover leftovers tightly and store in the refrigerator up to 4 days, or in the freezer up to 2 months. Thaw in fridge overnight and bake at 350ºF (177ºC) for about 20 minutes.